7S 



for the destruction of mosquito larvae ; aquarium experi- 

 ments were continued in a pond of considerable size and 

 from the data obtained Mr. Wilson read a very practical 

 paper at the " All India Malaria Conference" in Madras 

 city which are now found to be free from larvae ; he also 

 supplied a number of Municipalities with the necessary 

 fish carriers for stocking- purposes. His paper shows 

 that the Chelaeargentea is a most efficient larvicide, and 

 that his ponds, of considerable size, are kept entirely 

 free from mosquito larvae, chiefly by their activity ; 

 besides these the various species of Haplochilus are 

 very useful and can be transported to long distances ; 

 for brackish and salt waters and swamps he recommends 

 the Therapon jdj^biia. 



Madras fresh-water pisciculture is a most difficult 

 subject owing mainly to the non-permanence of its waters 

 and their use in irrigation ; hence the framing and 

 execution of practical projects is a matter of great difficulty 

 which Mr. Wilson is gradually overcoming. 



1/ Pearl and chank /iskejy. — The supervision of 

 operations in this branch is Mr. Hornell's work ; these 

 are separately and fully reported on as usual. The year 

 was one of comparatively poor yield owing mainly to 

 unpropitious weather and the increasing difficulties of 

 obtaining divers. The net profit was Rs. 10,124 to 

 which the motor-boat Sutherland contributed largely by 

 towing canoes out in weather w^hen they could not 

 otherwise have reached the banks or returned from them. 

 Mr. Hornell's report deals in detail with the work, past 

 and prospective, in chanks and pearls, and it is hoped 

 that a new era will begin this year with the advent of 

 the new motor inspection vessel and with other ex- 

 pected advantages, in which the Tuticorin fish farm should 

 take a prominent part since the cultivation not merely 

 of the pearl oyster but of pearls will be a feature of the 

 operations under the skilled experiments of Mr. Hornell. 

 The South Arcot chank contractor duly paid his rental 

 and has now tendered for the Tanjore collection. 



During the year Mr. Hornell wrote the second and 

 a valuable part of his monograph on chanks, taking up 

 the matter from a social, industrial, and artistic point of 

 view ; this has been printed and is now before Govern- 

 ment ; also several articles on fish parasites, the cyclic 

 character of the pearl fisheries, etc. 



